The purpose of this study is to determine whether AZD1775 has any effect on the pharmacokinetics (PK) of three compounds (caffeine, omeprazole, and midazolam) that are probes for common drug-metabolizing enzymes (caffeine-CYP1A2, omeprazole-CYP2C19, midazolam-CYP3A). The study also seeks to determine the effect of AZD1775 on the QTc interval, which is a common measure of cardiac (heart) function.